The overall objective of this research project is to provide guidelines for the treatment of bacterial prostatitis with chemotherapeutic agents and antibiotics. A dog model has been developed by injecting Escherichia coli into the prostatic artery, thereby creating an acute prostatitis in the animal. The concentrations of various chemotherapeutic agents and antibiotics have then been measured in the plasma, urine, prostatic secretion and interstitial prostatic fluid of these animals. Prostatic secretion has been obtained following stimulation with pilocarpine. Interstitial fluid has been obtained by implanting small plastic chambers into the dog's prostate. In general, it has been found that the basic substances such as trimethoprim and erythromycin concentrate well, not only in the normal prostate, but also in the infected one, whereas acid substances with a low pKa such as sulfamethoxazole and ampicillin do not. Therefore, the basic substances may be effective in the treatment of bacterial prostatitis if the infecting bacteria are sensitive to them.